chore(deps): update dependency pytest-cov to >=6,<6.4 (#550)

This PR contains the following updates:

| Package | Change | Age | Confidence |
|---|---|---|---|
| [pytest-cov](https://redirect.github.com/pytest-dev/pytest-cov)
([changelog](https://pytest-cov.readthedocs.io/en/latest/changelog.html))
| `>=6,<6.3` -> `>=6,<6.4` |
[![age](https://developer.mend.io/api/mc/badges/age/pypi/pytest-cov/6.3.0?slim=true)](https://docs.renovatebot.com/merge-confidence/)
|
[![confidence](https://developer.mend.io/api/mc/badges/confidence/pypi/pytest-cov/6.2.1/6.3.0?slim=true)](https://docs.renovatebot.com/merge-confidence/)
|

---

### Release Notes

<details>
<summary>pytest-dev/pytest-cov (pytest-cov)</summary>

###
[`v6.3.0`](https://redirect.github.com/pytest-dev/pytest-cov/blob/HEAD/CHANGELOG.rst#630-2025-09-06)

[Compare
Source](https://redirect.github.com/pytest-dev/pytest-cov/compare/v6.2.1...v6.3.0)

- Added support for markdown reports.
Contributed by Marcos Boger in `#&#8203;712
<https://github.com/pytest-dev/pytest-cov/pull/712>`\_
and `#&#8203;714 <https://github.com/pytest-dev/pytest-cov/pull/714>`\_.
- Fixed some formatting issues in docs.
Anonymous contribution in `#&#8203;706
<https://github.com/pytest-dev/pytest-cov/pull/706>`\_.

</details>

---

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setup.py

@@ -49,7 +49,7 @@
             "coverage>=7.10,<7.11",
             "pylint>=3,<3.4",
             "pytest>=8,<8.5",
-            "pytest-cov>=6,<6.3",
+            "pytest-cov>=6,<6.4",
             "mypy>=1.17,<1.18",
             "types-python-dateutil",
             "types-requests",